The incidence of parasitic marine isopods among wild 100 Argyrops filamentosus fish was studied. Specimens were subjected to clinical, postmortem and parasitological examinations for detection of isopod infestations. The detected parasite was Cymothoa spinipalpa. The infestation rate was 9%, one per fish. Cymothoa spinipalpa was observed in the gill chamber and buccal cavity of the host. Slight protrusion of gill cover (operculum), atrophy and haemorrhage at site of attachment were noticed. The morphological characteristics of this species were described in details using light and scanning electron microscopy and discussed.